1. Technical Field
This invention is related generally to the field of pressure indicators and more specifically to the field of hydrostatic pressure indicators for showing if a certain pressure has been reached and/or if an item has been subjected to a certain pressure.
2. Prior Art
The use of high pressure pasteurization has become a standard method for destroying bacteria in foods. Current normal methods such as heating foods to destroy bacteria are known, and can alter the taste and texture of certain foods. For example, sliced lunch meats, such as turkey and chicken, and guacamole will be altered if exposed to high temperatures.
High pressure pasteurization or sterilization methods also are known. For example, foods and other items are packaged in sealed flexible poly bags. The bagged food then can be placed in an autoclave and hydrostatically pressurized using water as a medium to achieve a pressure of 85,000 psi for a period of time. Such a pressure will destroy the bacteria, thus increasing the shelf life of the bagged food. However, if the food did not get properly pressurized and was placed on the shelf and had active bacteria that caused sickness in consumers, it might result in a total recall of the packages. Because of this possibility, it is desirable to have an inexpensive irreversible indicator to show that every package had been exposed to 85,000 psi or any other desired pressure.